Not to be critical but why do you want to put a ˝" chuck onto a drill that was designed and built to use only a 3/8" chuck? Doing so would undoubtedly void your warranty and also the Limited Lifetime Service Agreement.
As far as the batteries are concerned, you'll experience longer run times with the X2 batteries. Unless you're using your tools on a daily basis at work, I can't see much of a benefit in buying some X2 batteries when you can recharge the ones you now have in 20 minutes.
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